Model train systems have been in existence for many years. During the long history of model train systems, technology has advanced to allow hobbyists to enjoy model trains with ever increasing realism. For instance, sound simulation is one aspect of model train systems that has benefited from significant advances over the years. The earliest model train systems lacked sound simulation capabilities. Later, miniature whistles, bells, and the like were added to imitate sounds that might be generated by a real-world train. Unfortunately, such miniature devices are limited in their ability to produce realistic sounds.
Further developments in model train sound simulation technology led to the use of speakers to play back sounds recorded from real-world trains. Using pre-recorded sounds has improved realism to some degree, but some shortcomings can be detected by even the casual observer. For example, the pre-recorded sounds tend to be looped. Hobbyists who play with the train for a sufficiently long period of time can often notice the repetition of certain sounds. In addition, in many systems using pre-recorded sounds, the sounds to be played back are selected as a function of user inputs, e.g., commands, only. Thus, for example, a horn sounds the same whether the model train is stopped or running at full speed.
Keeping up to date with the latest technology has conventionally required hobbyists to purchase new trains or, at least, new circuit boards, to upgrade their systems. As a result, the expense involved in keeping a model train system up-to-date has been relatively high. These costs have been particularly discouraging to certain beginning hobbyists who do not want to make a large commitment of money to a state of the art system, but do not want a model train system that they will have to replace altogether. Hobbyists who only want to upgrade certain aspects of their model train systems rather than the whole system have also been discouraged by these costs.